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Abstract:

A liquid droplet ejection apparatus performs a drawing operation on a
workpiece set on a set table by driving the ejection of a functional
liquid droplet ejection head in a head unit while moving the head unit in
a main scanning direction relative to the set table. The liquid droplet
ejection apparatus includes an ejection defect test unit for inspecting
an ejection defect of the functional liquid droplet ejection head. The
ejection defect test unit includes a drawn unit on which a predetermined
test pattern is drawn by test ejection from the functional liquid droplet
ejection head and ejection-defect determination means for determining the
ejection defect by capturing an image of the test pattern drawn on the
ejection-defect test unit and recognizing the image. The drawn unit is
disposed on a scan moving axis offset from the set table towards the main
scanning direction.

Claims:

1. A liquid droplet ejection apparatus for performing a drawing operation
on a workpiece by ejecting functional liquid droplets comprising:a set
table on which the workpiece is set and is movable on an axis; anda head
unit which includes a functional liquid droplet ejection head and is
movable on an axis which crosses the set table;wherein one drawing line
length of the head unit corresponds to a maximum width of the workpiece
to be set on the set table.

2. The liquid droplet ejection apparatus according to claim 1 further
comprising a periodic flushing unit having a length corresponding to the
one drawing line length.

3. The liquid droplet ejection apparatus according to claim 2, wherein the
periodic flushing unit is disposed on the same moving axis as the set
table.

4. The liquid droplet ejection apparatus according to claim 3, wherein the
set table and the periodic flushing unit are independently movable.

5. The liquid droplet ejection apparatus according to claim 1 further
comprising an ejection-defect test unit having a length corresponding to
the one drawing line length and has a drawn unit.

6. The liquid droplet ejection apparatus according to claim 5, wherein the
drawn unit is disposed on the same moving axis as the set table.

7. The liquid droplet ejection apparatus according to claim 6, wherein the
set table and the drawn unit are independently movable.

8. The liquid droplet ejection apparatus according to claim 1, wherein the
head unit includes a plurality of carriage units each of which has the
functional liquid droplet ejection head.

9. The liquid droplet ejection apparatus according to claim 8, wherein
each of the plurality of carriage units is independently movable on the
same axis.

Description:

[0001]This application is a divisional of U.S. patent application Ser. No.
11/221,205 filed on Sep. 7, 2005. This application claims the benefit of
Japanese Patent Application No. 2004-260998 filed Sep. 8, 2004. The
disclosures of the above applications are incorporated herein by
reference.

BACKGROUND OF THE INVENTION

[0002]1. Field of the Invention

[0003]The present invention relates to a liquid droplet ejection apparatus
including an ejection defect test unit for inspecting the ejection defect
of a functional liquid droplet ejection head that ejects functional
liquid onto a workpiece, a method for manufacturing an electro-optic
device, an electro-optic device, and an electronic equipment.

[0004]2. Description of the Related Art

[0005]There is known a liquid droplet ejection apparatus which is used to
manufacture a variety of products (e.g., a color filter of a liquid
crystal display device) by a liquid droplet ejection method using a
functional liquid droplet ejection head. The liquid droplet ejection
apparatus includes an X-axis direction moving mechanism which moves a
substrate transport table (set table), on which a substrate (workpiece)
is set, in the X-axis direction and a Y-axis direction moving mechanism
which moves a head unit, on which the functional liquid droplet ejection
head is mounted, in the Y-axis direction. The area where the moving area
of the head unit and the moving area of the substrate transport table
overlap is a liquid droplet ejection area where drawing (picturing) can
be carried out on the substrate. By driving the ejection of the
functional liquid droplet ejection head while relatively moving the head
unit and the substrate, the liquid droplet ejection apparatus can draw a
predetermined drawing pattern on the substrate located in the liquid
droplet ejection area.

[0006]The liquid droplet ejection apparatus also includes a dot defect
detection unit for inspecting a nozzle clog of the functional liquid
droplet ejection head. The dot defect detection unit is located under the
moving area of the head unit and at a position shifted from the moving
area of the substrate transport table. The dot defect detection unit
includes a light receiving unit for causing each ejection nozzle of the
functional liquid droplet ejection head to eject functional droplets for
testing to optically detect the presence of the functional liquid droplet
and a test liquid receiving unit for receiving the functional droplets
for testing. When the dot defect inspection is carried out, the head unit
is moved to a position immediately above the test liquid receiving unit.
The ejection of the functional liquid droplet ejection head is then
driven so that each nozzle of the functional liquid droplet ejection head
ejects a functional droplet for testing onto the test liquid receiving
unit and the light receiving unit detects the presence of the functional
liquid droplet ejected from each nozzle (see, for example,
JP-A-2004-202325).

[0007]To increase the manufacturing yield of the drawing, it is desirable
that the dot defect detecting operation is regularly carried out in
addition to being carried out at the start-up time of the liquid droplet
ejection apparatus. That is, it is desirable that the dot defect
detecting operation is carried out when a workpiece is mounted on the set
table and dismounted from the set table so that the proper ejection of
functional liquid from the functional liquid droplet ejection head is
inspected before starting the next drawing operation. However, in the
known liquid droplet ejection apparatuses, the dot defect detection unit
is located at a position shifted from the moving area of the substrate
transport table. Therefore, the known liquid droplet ejection apparatuses
need to drive the Y-axis direction moving mechanism to move the head unit
in the drawing area to the dot defect detection unit when detecting the
dot defect in an interval between the drawing operations on a workpiece.
The known liquid droplet ejection apparatuses also need to drive the
Y-axis direction moving mechanism again to move the head unit to the
drawing area after the dot defect detection. Accordingly, in the known
liquid droplet ejection apparatuses, a cycle time for the dot defect
detection is increased, and therefore, the efficiency of the drawing
operation on the workpiece deteriorates.

SUMMARY OF THE INVENTION

[0008]Accordingly, it is an advantage of the invention to provide a liquid
droplet ejection apparatus, a method for manufacturing an electro-optic
device, an electro-optic device, and an electronic equipment for
efficiently detecting a dot defect even in the interval between drawing
operations on a workpiece and reducing a cycle time for detecting the dot
defect.

[0009]According to one aspect of this invention, there is provided a
liquid droplet ejection apparatus for performing a drawing operation on a
workpiece set on a set table by moving a head unit including a functional
liquid droplet ejection head having a plurality of ejection nozzles in a
scanning direction relative to the set table and by driving the ejection
nozzles to eject functional liquid on the workpiece facing the head unit.
The apparatus comprises an ejection-defect test unit for inspecting an
ejection defect of the functional liquid droplet ejection head, the
ejection-defect test unit comprising a drawn unit on which a
predetermined test pattern is drawn by test ejection from all of the
ejection nozzles of the functional liquid droplet ejection head and
ejection-defect determination means for determining an ejection defect of
the functional liquid droplet ejection head by capturing an image of the
test pattern drawn on the drawn unit and recognizing the image. The drawn
unit is disposed on a scan moving axis offset from the set table towards
the scanning direction.

[0010]According to this arrangement, since the drawn unit on which the
test pattern is drawn is disposed on a scan moving axis offset from the
set table towards the scanning direction, the liquid droplet ejection
apparatus allows the head unit to face the drawn unit by using a moving
axis of the head unit. Consequently, the head unit can use a relative
movement of the head unit in the scanning direction for drawing on the
workpiece so as to allow the head unit to efficiently and rapidly face
the drawn unit, and therefore, the time required for the ejection defect
inspection can be reduced. As a result, the total tact time can be
reduced, thus increasing the drawing efficiency on the workpiece.

[0011]Preferably, the liquid droplet ejection apparatus further includes a
scan moving table having a slider for supporting the set table and the
drawn unit and the scan moving table moves the set table and the drawn
unit in the scanning direction relative to the head unit.

[0012]According to this arrangement, since the drawn unit and the set
table are supported by the same slider, the forward and backward movement
of the slider for the drawing operation in the X-axis direction moves the
drawn unit in the X-axis direction. Consequently, when inspecting an
ejection defect of the functional liquid droplet ejection head, the
liquid droplet ejection apparatus can cause the drawn unit to face the
head unit by using the movement of the set table in the scanning
direction.

[0013]Preferably, the liquid droplet ejection apparatus further includes a
scan moving table having a slider for supporting the set table and the
drawn unit and the scan moving table moves the set table and the drawn
unit in the scanning direction relative to the head unit. The slider
includes a first slider for supporting the set table movably in the
scanning direction and a second slider independently controlled from the
first slider for supporting the drawn unit movably in the scanning
direction.

[0014]According to this arrangement, since the drawn unit is supported by
the slider different from the slider that supports the set table, the
load for moving each slider can be reduced. Additionally, since the first
slider and the second slider can independently move in the X-axis
direction, the set table can be moved along with a periodic flushing unit
or can be moved separately from the periodic flushing unit. In this case,
by moving the ejection defect test unit in synchronization with the
movement of the set table moving away from the head unit, the ejection
defect test unit can efficiently face the head unit to rapidly perform
the ejection defect inspection. The ejection defect test unit need not
move during the drawing process on the workpiece.

[0015]Preferably, the liquid droplet ejection apparatus further includes
control means for controlling the functional liquid droplet ejection head
and the scan moving table. A workpiece exchange position at which the
workpiece is mounted and dismounted on the set table is defined on the
scan moving axis and the drawn unit is disposed so that the set table
faces the head unit while the set table moves to the workpiece exchange
position. The control means drives the functional liquid droplet ejection
head to eject and draw the test pattern when the drawn unit moving to the
workpiece exchange position faces the head unit.

[0016]According to this arrangement, when the set table moves to the
workpiece exchange position, the drawn unit can face the head unit so
that the head unit can draw a test pattern on the drawn unit.
Consequently, the head unit need not move in order to draw the test
pattern. Thus, an ejection defect of the functional liquid droplet
ejection head can be inspected by using the movement of the set table
moving to the workpiece exchange position.

[0017]Preferably, the ejection-defect determination means is disposed so
that the ejection-defect determination means faces the drawn unit when
the set table reaches the workpiece exchange position, and the control
means controls the ejection-defect determination means to determine an
ejection defect during an operation for mounting and dismounting the
workpiece.

[0018]According to this arrangement, since the image capturing of the test
pattern and the determination of the ejection defect of the functional
liquid droplet ejection head are carried out during an operation for
mounting and dismounting the workpiece, the ejection defect can be
efficiently inspected by using the workpiece mounting and dismounting
time.

[0019]Preferably, the liquid droplet ejection apparatus further includes a
periodic flushing unit for receiving the ejection from the ejection
nozzles of the functional liquid droplet ejection head and the periodic
flushing unit includes a periodic flushing box disposed to face the head
unit when the set table reaches the workpiece exchange position. The
control means drives the functional liquid droplet ejection head to
perform the ejection during the operation for mounting and dismounting
the workpiece.

[0020]According to this arrangement, since the ejection (forcible
ejection) onto the periodic flushing box is carried out during the
operation for mounting and dismounting the workpiece, the clogging of the
functional liquid droplet ejection head due, for example, to drying can
be reliably prevented during the operation for mounting and dismounting
the workpiece.

[0021]Preferably, the liquid droplet ejection apparatus further includes a
maintenance unit for performing the maintenance of the functional liquid
droplet ejection head while facing the head unit and head moving means
for moving the head unit to face the maintenance unit. The control means
controls the and the head moving means, causes the head unit to face the
maintenance unit when the ejection-defect determination means determines
the ejection defect, and causes the maintenance unit to maintain the
functional liquid droplet ejection head.

[0022]According to this arrangement, when an ejection defect of the
functional liquid droplet ejection head is determined, the ejection
defect can be recovered by moving the head unit to the maintenance unit
to maintain the head unit. Additionally, by mounting the maintenance unit
on the scan moving table, the scan moving table can function as the head
moving means.

[0023]Preferably, the maintenance unit includes at least one of a suction
unit for sucking the functional liquid droplet ejection heads to force
the ejection nozzles to discharge the functional liquid and a wiping unit
for wiping nozzle surfaces of the functional liquid droplet ejection
head.

[0024]According to this arrangement, if the suction unit is mounted as the
maintenance unit, the clogging of the functional liquid droplet ejection
head can be recovered by forcing the ejection nozzles to discharge the
functional liquid. If the wiping unit is mounted as the maintenance unit,
a misdirected jet of the functional liquid from the functional liquid
droplet ejection head can be recovered by wiping out dust and dirt on the
nozzle surface of the functional liquid droplet ejection head.

[0025]Preferably, the plurality of ejection nozzles of the head unit are
continuously arranged in a direction perpendicular to the scanning
direction in order to draw one drawing line and the length of the drawn
unit in the direction perpendicular to the scanning direction is
determined so as to correspond to the length of the one drawing line.

[0026]According to this arrangement, the drawn unit can receive functional
liquid ejected from all of the functional liquid droplet ejection head of
the head unit. Thus, the test pattern can be efficiently drawn.

[0027]Preferably, the ejection-defect determination means includes a
camera facing the drawn unit from above and a camera moving mechanism for
supporting the camera movably in a direction perpendicular to the
scanning direction.

[0028]According to this arrangement, by moving the camera facing the drawn
unit from above in a direction perpendicular to the scanning direction,
all of the image of the test pattern can be captured.

[0029]Preferably, the camera moving mechanism includes two of the cameras
arranged in a direction perpendicular to the scanning direction.

[0030]According to this arrangement, the image of the test pattern can be
efficiently captured by using the two cameras mounted on the camera
moving mechanism. As a result, the time required for capturing the image
can be reduced.

[0031]Preferably, the ejection-defect test unit further includes a unit
moving mechanism for moving the drawn unit in the scanning direction.

[0032]According to this arrangement, since the drawn unit can move in the
scanning direction, the drawn unit can draw a plurality of test patterns
in the scanning direction. That is, even when the plurality of test
patterns are drawn in the scanning direction while shifting the test
patterns to each other in the scanning direction, the shifts can be
canceled by moving the drawn unit in the scanning direction. Thus, the
image of the test pattern can be properly recognized.

[0033]According to another aspect of the invention, there is provided a
method for manufacturing an electro-optic device comprising forming a
coating portion on the workpiece with droplets of functional liquid by
using the above-described liquid droplet ejection apparatus.

[0034]According to still another aspect of the invention, there is
provided an electro-optic device comprising a coating portion formed on a
workpiece with functional liquid droplets by using the above-described
liquid droplet ejection apparatus.

[0035]According to this arrangement, since the above-described liquid
droplet ejection apparatus is employed, the ejection defect of the
functional liquid droplet ejection head can be efficiently inspected.
Additionally, the coating portion can be precisely formed by using the
normal functional liquid droplet ejection head, and therefore, the
electro-optic device can be efficiently manufactured. Examples of the
electro-optic devices include a liquid crystal display device, an organic
electroluminescent (EL) device, an electron emission device, a plasma
display panel (PDP) device, and an electrophoretic display device. The
electron emission device refers to a device such as a field emission
display (FED) and a surface-conduction electron-emitter display (SED). In
addition, examples of the electro-optic apparatuses include devices for
forming metal wiring, a lens, a resist, and a light diffuser.

[0036]According to still another aspect of the invention, there is
provided an electronic equipment comprising one of an electro-optic
device manufactured by using the above-described method and the
above-described electro-optic device.

[0037]In this case, the electronic equipment corresponds to a cell phone,
a personal computer, or a variety of electronic products having mounted
thereon a flat panel display.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038]FIG. 1 is an external perspective view of a liquid droplet ejection
apparatus according to an embodiment of the invention when a set table
(suction table) is located at a workpiece exchange position;

[0039]FIG. 2 is a plan view of the liquid droplet ejection apparatus when
the set table (suction table) is located at the workpiece exchange
position and a bridge plate is removed;

[0040]FIG. 3 is a side view of the liquid droplet ejection apparatus when
the set table (suction table) is located at the workpiece exchange
position;

[0045]FIGS. 8A, 8B, and 8C illustrate a drawing process of the liquid
droplet ejection apparatus, where FIG. 8A is a schematic plan view
illustrating a first drawing operation, FIG. 8B is a schematic plan view
illustrating a second drawing operation, and FIG. 8C is a schematic plan
view illustrating a third drawing operation;

[0046]FIG. 9 is an external perspective view of an X-axis air slider and
its vicinity;

[0047]FIG. 10 is a block diagram of a main control system of a drawing
apparatus;

[0048]FIG. 11 is a flow chart illustrating the manufacturing steps of the
color filter;

[0049]FIGS. 12A through 12E are schematic cross-sectional views of a color
filter in manufacturing steps;

[0050]FIG. 13 is a cross-sectional view of an essential part of the
structure of a liquid crystal device including a color filter according
to an embodiment of the invention;

[0051]FIG. 14 is a cross-sectional view of an essential part of a second
example of the liquid crystal device including a color filter according
to an embodiment of the invention;

[0052]FIG. 15 is a cross-sectional view of an essential part of a third
example of the liquid crystal device including a color filter according
to an embodiment of the invention;

[0053]FIG. 16 is a cross-sectional view of an essential part of an organic
EL display device;

[0054]FIG. 17 is a flow chart illustrating the manufacturing steps of the
organic EL display device;

[0055]FIG. 18 illustrates a step for forming an inorganic bank layer;

[0056]FIG. 19 illustrates a step for forming an organic bank layer;

[0057]FIG. 20 illustrates a step for forming a
hole-injecting/hole-transporting layer;

[0058]FIG. 21 illustrates a state after forming the
hole-injecting/hole-transporting layer;

[0060]FIG. 23 illustrates a state after forming the blue light-emitting
layer;

[0061]FIG. 24 illustrates a state after forming light-emitting layers for
three color components;

[0062]FIG. 25 illustrates a step for forming a negative electrode;

[0063]FIG. 26 is an exploded perspective view of an essential part of a
plasma display device (PDP device);

[0064]FIG. 27 is a cross-sectional view of an essential part of an
electron emission device (FED device); and

[0065]FIG. 28A is a plan view of an electron emission unit of the electron
emission device, and FIG. 28B is a plan view illustrating a method for
forming the electron emission unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066]A liquid droplet ejection apparatus according to the invention is
described below with reference to the accompanying drawings. The liquid
droplet ejection apparatus is used in a manufacturing line of a flat
display. By adopting the liquid droplet ejection method using a
functional liquid droplet ejection head, the liquid droplet ejection
apparatus is used to manufacture a color filter of a liquid crystal
display device for three colors, namely, red (R), green (G), and blue
(B), or light emitting elements functioning as pixels of an organic
electroluminescent (EL) display on a workpiece (substrate).

[0067]As shown in FIGS. 1 through 3, a liquid droplet ejection apparatus 1
is installed on an X-axis support base 2 (stone bed). The liquid droplet
ejection apparatus 1 includes an X-axis table 11 (main scan moving means)
which extends in the X-axis direction (main scanning direction) and which
moves a workpiece W in the X-axis direction; a Y-axis table 12 (sub scan
moving means) mounted on two Y-axis support bases 3, which bridge over
the X-axis table 11 by a plurality of support rods, while extending in
the Y-axis direction (sub scanning direction); and a head unit 13 which
includes seven carriage units 81 on which a plurality of functional
liquid droplet ejection heads 82 (not shown) are mounted and which is
movably supported by the Y-axis table 12 in the Y-axis direction (sub
scanning direction). The liquid droplet ejection apparatus 1 controls the
ejection of the functional liquid droplet ejection head 82 in
synchronization with the drive of the X-axis table 11 and the Y-axis
table 12 so that the functional liquid droplet ejection head 82 ejects
functional liquid droplets for R, G, and B colors to draw a predetermined
drawing pattern on the workpiece W (a drawing process).

[0068]The liquid droplet ejection apparatus 1 further includes a flushing
unit 14, a suction unit 15, a wiping unit 16, an ejection-defect test
unit 17 (hereinafter collectively referred to as maintenance means).
These units are used for maintaining the functional liquid droplet
ejection head 82 so that the function of the functional liquid droplet
ejection head 82 is maintained or recovered (a maintenance process).
Among these units serving as the maintenance means, the flushing unit 14
and the ejection-defect test unit 17 are mounted on the X-axis table 11
whereas the suction unit 15 and the wiping unit 16 are arranged on a
platform 5 located at a position which is away from the X-axis table 11
and to which the Y-axis table 12 can move the head unit 13.

[0069]The liquid droplet ejection apparatus 1 includes control means 18
for carrying out overall control of the apparatus (not shown). The
above-described drawing process and maintenance process are carried out
under the control of the control means 18.

[0070]The constituent elements of the liquid droplet ejection apparatus 1
are described next. As shown in FIGS. 1 through 3, the X-axis table 11
includes a set table 21 on which the workpiece W is set, an X-axis air
slider 22 for slidably supporting the set table 21 in the X-axis
direction, left and right X-axis linear motors (not shown) which extend
in the X-axis direction and which move the workpiece W in the X-axis
direction via the set table 21, and a pair (two) of X-axis guide rails 23
which extend along the X-axis linear motors and guide the movement of the
X-axis air slider 22.

[0071]The set table 21 includes a suction table 31 for sucking and setting
the workpiece W and a θ table 32 for supporting the suction table
31 and correcting the position of the workpiece W set on the suction
table 31 in the θ-axis direction. As shown in FIG. 9, the suction
table 31 includes a table body 41 for sucking and setting the workpiece
W, three sets of table supporting members (not shown) for supporting the
table body 41 at three points, and a support base 42 which is fixed to
the θ table 32 and which supports the table body 41 via the table
supporting members. The table body 41 is composed of a thick stone plate
and is substantially square having sides of 1800 mm in plan view. A
plurality of suction guide grooves 43 are formed on the surface of the
table body 41 to suck the workpiece W. An air drawing port (not shown) is
formed in each of the suction guide grooves 43 while passing through it
to communicate with the air drawing means. Thus, a sufficient suction
force can be applied to the workpiece W through the suction guide grooves
43.

[0072]The support base 42 supports a pre-drawing flushing unit 111, which
is described below, as well as the three sets of table supporting
members. A pre-drawing flushing box 121 of the pre-drawing flushing unit
111, which is described below, is attached to each side of the table body
41 parallel to the Y-axis. A plurality of lifter pins (not shown) of a
lifter mechanism (not shown) are loosely inserted into a plurality of
loose insertion holes 44. The suction table 31 incorporates a lifter
mechanism for providing a workpiece to the suction table 31 or removing
the workpiece from the suction table 31. The lifter mechanism is
supported by the support base 42 and has the plurality of lifter pins
which can freely move up and down. By protruding the plurality of lifter
pins from the plurality of loose insertion holes 44 formed in the table
body 41, the lifter mechanism receives an unprocessed workpiece W from a
robot arm (not shown) and transfers it to the suction table 31. The
lifter mechanism also lifts a processed workpiece W off the set table 21
and transfers it to the robot arm.

[0073]As shown in FIGS. 1 and 3, the X-axis air slider 22 includes a
slider body 51 for supporting the set table 21 (θ table 32) and two
pairs of engaging portions 52 (i.e., four engaging portions) secured to
the lower portion of the slider body 51 and engaged with the pair of
X-axis guide rails 23. As well as the set table 21, the slider body 51
includes a periodic flushing unit 112 of the flushing unit 14 and a drawn
unit 161 of the ejection-defect test unit 17, both of which are described
below. When the pair of the X-axis linear motors is synchronously
activated, the X-axis air slider 22 moves in the X-axis direction while
the pair of the engaging portions 52 is guided by the pair of the X-axis
guide rails 23 so that the workpiece W set on the set table 21 moves in
the X-axis direction (main scanning movement).

[0074]At the bottom of FIG. 2 is a workpiece exchange position 61 where
the workpiece W is to be mounted or dismounted. When an unprocessed
workpiece W is mounted on the suction table 31 or a processed workpiece W
is collected, the suction table 31 is moved to that position. Workpiece
alignment cameras 62 shown in FIG. 2 recognize the position of the
workpiece W. The θ table 32 performs θ correction of the
workpiece W on the basis of an image captured by the workpiece alignment
cameras 62.

[0075]The Y-axis table 12 includes seven bridge plates 71, each of which
allows the carriage unit 81 (a carriage 85) of the head unit 13 to pass
through and securely holds it; seven pairs of (fourteen) Y-axis sliders
(not shown) which support the seven bridge plates 71 at the both ends
thereof; a pair of Y-axis linear motors (not shown) which is mounted on
the pair of Y-axis support bases 3 and which moves the bridge plates 71
in the Y-axis direction via the seven pairs of (fourteen) Y-axis sliders;
and a pair of Y-axis guide rails (not shown) which is mounted on the
Y-axis support bases 3 parallel to the Y-axis linear motors and which
supports the seven pairs of (fourteen) Y-axis sliders to guide the
movement of each Y-axis slider.

[0076]When the pair of the Y-axis linear motors is synchronously driven,
each Y-axis slider is guided by the pair of Y-axis guide rails and
translates in the Y-axis direction. Thus, the bridge plates 71 move while
the both ends thereof are supported. Along with the bridge plates 71, the
carriage unit 81 moves in the Y-axis direction (sub scan movement). In
this case, by controlling the drive of the Y-axis linear motors, the
bridge plates 71 (carriage units 81) can be independently moved.
Alternatively, the seven bridge plates 71 can be moved as one body.

[0077]As shown in FIGS. 1 through 3, the head unit 13 includes the seven
carriage units 81 having the same structure arranged in the Y-axis
direction. Each of the carriage units 81 includes twelve functional
liquid droplet ejection head 82 (not shown), six head holding plates 83
(not shown) each of which holds two functional liquid droplet ejection
head 82, a head plate 84 having the twelve functional liquid droplet
ejection head 82 via the six head holding plates 83, and the carriage 85
for supporting the head plate 84.

[0078]As shown in FIG. 4, the functional liquid droplet ejection head 82
has a twin structure. The functional liquid droplet ejection head 82
includes a functional liquid introducing unit 91 having a twin connection
pin 92, a twin-head substrate 93 connected to the functional liquid
introducing unit 91, and a head body 94 including an in-head flow channel
which communicates with the bottom of the functional liquid introducing
unit 91 and which is filled with functional fluid. The connection pins 92
are connected to a functional liquid tank (not shown) and supply the
functional liquid introducing unit 91 with the functional fluid. The head
body 94 includes a cavity 95 (piezoelectric device) and a nozzle plate 96
having a nozzle surface 97 on which openings of a plurality of ejection
nozzles 98 are formed. When the ejection of the functional liquid droplet
ejection head 82 is activated, a voltage is applied to the piezoelectric
device and the cavity 95 functions as a pump. As a result, functional
liquid droplets are ejected from the ejection nozzles 98.

[0079]The plurality of the ejection nozzles 98 formed on the nozzle
surface 97 are arranged at an even pitch (2 dots per pitch) and form two
separated nozzle lines 98b, each of which includes 180 ejection nozzles
98. The two separated nozzle lines 98b are shifted to each other by one
dot pitch. That is, the functional liquid droplet ejection head 82
provides a nozzle line 98a having one dot pitch formed by the two
separated nozzle lines 98b. Thus, the high-resolution drawing (one dot
pitch) can be provided.

[0080]Each of the six head holding plates 83 is composed of, for example,
a thick stainless plate and has a rectangular shape in plan view. Two
mounting openings (not shown) for respectively positioning and mounting
the two functional liquid droplet ejection heads 82 are formed on the
head holding plates 83 in the length direction thereof. The two mounting
openings have a nozzle line pitch for six heads.

[0081]As shown in FIG. 5, the head plate 84 is composed of, for example, a
thick stainless plate and appears to be substantially
parallelogram-shaped when viewed in top plan. Two mounting openings (not
shown) for positioning and mounting the head holding plates 83 are formed
on the head plate 84. Six head holding plates 83 are arranged in a
staircase pattern while being shifted to each other by a nozzle line
length L for about one head (in a direction of the nozzle line of the
functional liquid droplet ejection head 82). Thus, the nozzle line 98a of
twelve functional liquid droplet ejection heads 82 mounted on each of the
head plates 84 forms a line in the Y-axis direction (partly overlapped).
As a result, a single divided drawing line is formed.

[0082]The carriage 85 includes a θ rotation mechanism 101 for
rotatably supporting the head plate 84 by θ correction (θ
rotation) and a hanging member 102 for allowing the Y-axis table 12 (each
of the bridge plates 71) to support the head plate 84 via the θ
rotation mechanism 101. The θ rotation mechanism 101 supports the
head plate 84 so that the divided drawing line is parallel to the Y-axis
direction. Although not shown, the hanging member 102 incorporates a head
elevation mechanism (not shown) for lifting the head plate 84 via the
θ rotation mechanism 101 so that the height level of the head plate
84 (the nozzle surface 97 of the functional liquid droplet ejection head
82) can be adjusted.

[0083]The seven carriages 85 are supported by the seven bridge plates 71,
respectively, and the seven carriage units 81 are aligned in the Y-axis
direction. Thus, the head unit 13 is formed. In the head unit 13,
12×7 functional liquid droplet ejection heads 82 are continuously
arranged in the Y-axis direction and seven divided drawing lines of the
carriage units 81 are connected in the Y-axis direction to form one
drawing line. The left side position of the X-axis table 11 in FIG. 2
(the platform 5 side) is the home position of the head unit 13. The
drawing process on the workpiece W starts from this position.

[0084]Each of the 12×7 functional liquid droplet ejection heads 82
mounted on the head unit 13 corresponds to functional liquid of either R,
G, or B color so that a drawing pattern formed from functional liquid of
three colors can be written on the workpiece W. FIG. 6 illustrates a
color pattern of the functional liquid droplet ejection heads 82 of the
head unit 13 according to this embodiment. As shown in FIG. 6, in the
color pattern of the functional liquid droplet ejection heads 82 of the
head unit 13, three colors, namely, R, G, and B colors are repeatedly
assigned to the 12×7 functional liquid droplet ejection heads 82 in
a predetermined order (R, G, and B from the right of FIG. 6 in this
embodiment). The color pattern of the functional liquid droplet ejection
heads 82 for each of the seven carriage units 81 is identical to each
other.

[0085]Accordingly, by moving the head unit 13 in the sub scanning
direction by a nozzle line length for two heads, the functional liquid
droplet ejection heads 82 for R, G, and B colors can face the area which
the third and later functional liquid droplet ejection heads 82
previously faced. Thus, a drawing pattern of three colors can be written
in this area. Therefore, in this embodiment, the length of a drawing line
is determined so that the sub scan movement for two-head nozzle line
length can complete a drawing process for one workpiece W. More
specifically, the drawing line length is determined on the basis of the
maximum width of the workpiece W that can be set on the set table 21.
That is, the drawing line length is determined to be a nozzle line length
(i.e., the minimum value for n heads) that allows drawing for the
workpiece W having the maximum width by one main scan movement plus the
nozzle line length for two heads (i.e., (n+2)×L). In this
embodiment, n=82.

[0086]Additionally, since the number of the head holding plates 83 in the
head plate 84 (i.e., 6) is an integer multiple of the number of colors
(i.e., 3), functional liquid of one color corresponds to two functional
liquid droplet ejection heads 82 held by one head holding plate 83. Thus,
the pipe arrangement between the functional liquid tank and each of the
functional liquid droplet ejection heads 82 can be simplified.

[0087]A series of drawing processes of the liquid droplet ejection
apparatus 1 is described next with reference to FIG. 8 when a color
filter of a liquid crystal display device is produced. The processes are
briefly described here, although the detailed description is provided
later. A color filter 600 includes a transparent substrate 601, a
plurality of pixel areas (filter elements) 607a arranged in a matrix in
the X-axis and Y-axis directions on the workpiece W, coloring layers 608
for R, G, and B colors (608R, 608G, and 608B) formed on each pixel area
607a, and a light-shielding bank 603 for separating the pixel areas 607a
(see FIGS. 8 and 12). In a drawing process, a substrate 603 which has
already had the bank 603 is used as the workpiece W. A predetermined
drawing pattern is written on the workpiece W such that functional liquid
of one of R, G, and B colors is ejected onto each pixel area 607a.

[0088]As shown in FIGS. 7A-7C, three color patterns of the color filter
are available as follows: a stripe arrangement in which a transverse line
of the pixel areas 607a parallel to the Y-axis direction has the same
color. R, G, and B colors are repeatedly assigned to the transverse lines
in the X-axis direction; a mosaic arrangement in which every three R, G,
and B consecutive pixel areas 607a are arranged in the X-axis direction
and the Y-axis direction; and a delta arrangement in which a plurality of
the pixel areas 607a are arranged in a hound's-tooth pattern while being
shifted to each other by a half pitch. R, G, and B colors are differently
assigned to three consecutive pixel areas 607a. In this embodiment, a
color filter of the stripe arrangement is manufactured.

[0089]The drawing process starts after the workpiece W (the suction table
31) is moved from the workpiece exchange position. A first drawing
operation starts first. In the first drawing operation, the X-axis table
11 is continuously driven. The workpiece W moves forward via the set
table 21. In synchronization with this movement, the functional liquid
droplet ejection head 82 of the head unit 13 at the home position is
selectively driven to eject functional liquid onto the workpiece W. Upon
completion of the forward movement of the workpiece W, the Y-axis table
12 is driven so that the head unit 13 slightly moves in the Y-axis
direction. Thereafter, the X-axis table 11 is driven again. In
synchronization with this movement, the functional liquid droplet
ejection head 82 is selectively driven to eject the functional liquid
onto the workpiece W moving backward. Upon completion of the backward
movement of the workpiece W, the Y-axis table 12 is further driven so
that the head unit 13 slightly moves in the Y-axis direction. The
above-described series of operations is repeated. Finally, the first
drawing operation is completed.

[0090]As shown in FIG. 8A, a drawing line of the head unit 13 is
perpendicular to a longitudinal line of the pixel areas 607a formed in a
matrix on the workpiece W, and therefore, the functional liquid droplet
ejection heads 82 face each line of the pixel areas. Additionally, when
the head unit 13 is located at the home position, the two rightmost
functional liquid droplet ejection heads 82 in the drawing (leftmost in
FIG. 2) are further shifted right from the rightmost pixel area line.
When the above-described first drawing operation is carried out, the
functional liquid droplet ejection heads 82 face the lines, respectively.
Thus, the functional liquid is ejected to the pixel areas 607a
corresponding to the same color as that of the functional liquid droplet
ejection head 82.

[0091]Upon completion of the first drawing operation, the Y-axis table 12
is driven so that the head unit 13 moves in the Y-axis direction by
substantially the head nozzle line length L. Thus, the functional liquid
droplet ejection head 82 for B color moves to the position which the
functional liquid droplet ejection heads 82 for R color has previously
faced in the first drawing operation. The functional liquid droplet
ejection head 82 for R color moves to the position which the functional
liquid droplet ejection heads 82 for G color has previously faced. The
functional liquid droplet ejection head 82 for G color moves to the
position which the functional liquid droplet ejection heads 82 for B
color has previously faced. Subsequently, a second drawing operation is
carried out. In the second drawing operation, as in the first drawing
operation, the forward and backward motion of the workpiece W and the
ejection operation of the functional liquid droplet ejection heads 82 are
repeated twice. Thus, as shown in FIG. 8B, in the second drawing
operation, functional liquid of B color is ejected onto the pixel area
line to which functional liquid of R color was previously ejected.
Functional liquid of R color is ejected onto the pixel area line to which
functional liquid of G color was previously ejected. Functional liquid of
G color is ejected onto the pixel area line to which functional liquid of
B color was previously ejected.

[0092]Upon completion of the second drawing operation, the Y-axis table 12
is driven so that the head unit 13 further moves in the Y-axis direction
by substantially the head nozzle line length L. Thus, the functional
liquid droplet ejection head 82 for G color moves to the position which
the functional liquid droplet ejection heads 82 for R color has
previously faced in the first drawing operation. The functional liquid
droplet ejection head 82 for B color moves to the position which the
functional liquid droplet ejection heads 82 for G color has previously
faced. The functional liquid droplet ejection head 82 for R color moves
to the position which the functional liquid droplet ejection heads 82 for
B color has previously faced. Subsequently, a third drawing operation is
carried out. In the third drawing operation, as in the first and second
drawing operations, the forward and backward motion of the workpiece W is
repeated twice. Thus, functional liquid of R, G, and B color is ejected
onto every pixel area 607a in every pixel area line. Thus, the drawing
process on the workpiece W is completed. After the drawing process is
completed, the two leftmost functional liquid droplet ejection head 82 in
the drawing (rightmost in FIG. 2) of the head unit 13 (for G and B
colors) are further shifted to the left from the leftmost pixel area line
(see FIG. 8C).

[0093]As described above, in this embodiment, the color pattern for the
12×7 functional liquid droplet ejection heads 82 is created by a
repetition of three R, G, and B colors. Therefore, by simply moving the
head unit 13 by a nozzle line length for two heads (2L), functional
liquid for all colors can be ejected to all pixel areas 607a of the
workpiece W. In addition, since functional liquid for all colors is not
ejected to the pixel areas 607a in the same line (also the pixel areas
607a in a transverse line in the case of a stripe arrangement) at the
same time, a chance for mixing the colors is reduced even when the
functional liquid is ejected onto the bank 603. This is because the
functional liquid on the bank 603 dries due to a time difference.
Consequently, the color filer can be precisely manufactured.

[0094]In this embodiment, the drawing process is carried out by moving the
head unit 13 forward and backward with respect to the pixel areas 607a
twice. However, the number of the forward and backward movements can be
changed depending on required conditions.

[0095]The flushing unit 14, the suction unit 15, the wiping unit 16, and
the ejection-defect test unit 17, which are included in the maintenance
means, are described next. The flushing unit 14 receives functional
liquid ejected from all of the ejection nozzles 98 of the functional
liquid droplet ejection heads 82 when carrying out the forcible ejection
(flushing). The flushing unit 14 includes the pre-drawing flushing unit
111 and the periodic flushing unit 112.

[0096]The pre-drawing flushing unit 111 receives functional liquid ejected
by pre-drawing flushing, which is carried out by driving the ejection of
the functional liquid droplet ejection heads 82 of the head unit 13
immediately before the functional liquid is ejected onto the workpiece W.
As shown in FIGS. 1 to 3 and FIG. 9, the pre-drawing flushing unit 111
includes a pair of the pre-drawing flushing boxes 121 for receiving the
functional liquid and a pair of box supporting members (not shown) for
allowing the suction table 31 (the support base 42) to support the pair
of the pre-drawing flushing boxes 121. Each of the pre-drawing flushing
boxes 121 is a box having an elongated rectangular shape in plan view. An
absorbent material 123 which absorbs the functional liquid is attached to
the bottom surface of the pre-drawing flushing box 121. Since each of the
pre-drawing flushing boxes 121 is supported by the suction table 31 via
the box supporting member, the pre-drawing flushing box 121 rotates
together with the suction table 31 when the suction table 31 is rotated
by the θ table for the θ correction.

[0097]Each of the box supporting members supports the suction table 31
while extending beyond the suction table 31 so that each of the
pre-drawing flushing boxes 121 extends along two sides (peripheral edges)
of the suction table 31 parallel to the Y-axis direction. That is, the
two pre-drawing flushing boxes 121 are disposed so as to sandwich the
suction table 31 at the front and the back. When the workpiece W is moved
forward and backward in the X-axis direction, the functional liquid
droplet ejection heads 82 of the head unit 13 sequentially face the
pre-drawing flushing boxes 121 immediately before facing the workpiece W
so as to carry out the pre-drawing flushing.

[0098]In this case, the length of the long side of the pre-drawing
flushing boxes 121 is determined to be substantially the length of one
drawing line plus the nozzle line length for two heads (i.e.,
(n+4)×L) in order to receive the forcible ejection from all of the
functional liquid droplet ejection heads 82 during the drawing process.
That is, in the drawing process according to this embodiment, the head
unit 13 is moved in the Y-axis direction by the length for two functional
liquid droplet ejection heads 82. By allowing the pre-drawing flushing
boxes 121 to cover the length for one drawing line length plus the nozzle
line length for two heads, the pre-drawing flushing boxes 121 can cover
the ejection area in the Y-axis direction of the functional liquid
droplet ejection heads 82 facing any position during the drawing process.
Thus, stable ejection of the functional liquid droplet from the
functional liquid droplet ejection heads 82 can be provided, and
therefore, the drawing process can be precisely carried out on the
workpiece W.

[0099]Although not shown, each of the box supporting members includes a
box elevation mechanism for elevating the pre-drawing flushing boxes 121.
During the drawing process, that is, when receiving the pre-drawing
flushing, the box supporting member supports the pre-drawing flushing box
121 so that the top surface of the pre-drawing flushing boxes 121 is at
the same height level as the surface of the workpiece W set on the
suction table 31. During the non-drawing process, the box supporting
member supports the pre-drawing flushing box 121 so that the top surface
of the pre-drawing flushing boxes 121 is at a lower height level than the
top surface (set surface) of the suction table 31 (i.e., at a standby
position). Accordingly, the pre-drawing flushing boxes 121 can receive
the functional liquid for the pre-drawing flushing without spattering the
functional liquid outside. In addition, the pre-drawing flushing boxes
121 do not interfere with the mounting operation of the workpiece W
during the non-drawing process. When considering the expansion of the
absorbent material 123, the height level of the top surface of the
pre-drawing flushing box 121 may be slightly lower than that of the
workpiece W. However, the box elevation mechanism may be eliminated
depending on actual conditions.

[0100]As shown in FIGS. 1 through 3 and FIG. 9, the periodic flushing unit
112 is used to receive functional liquid of periodic flushing carried out
by the functional liquid droplet ejection heads 82 of the head unit 13
when the drawing process is temporarily stopped, for example, during the
mounting and dismounting operation of the workpiece W. The periodic
flushing unit 112 includes a periodic flushing box 131 for receiving the
functional liquid and a pair of box support rods 132 mounted in the
X-axis air slider 22. The box support rods 132 support both ends of the
periodic flushing box 131 so that the height of the periodic flushing box
131 is adjustable.

[0101]The periodic flushing box 131 is an open-topped box with a
rectangular shape having a long side in the Y-axis direction in plan
view. The periodic flushing box 131 has a size that can contain all of
the 12×7 functional liquid droplet ejection heads 82 mounted in the
head unit 13. The periodic flushing box 131 can allow all of the
functional liquid droplet ejection heads 82 to carry out periodic
flushing at the same time. More specifically, like the pre-drawing
flushing boxes 121, the length of the long side of the periodic flushing
box 131 is determined to be the length of one drawing line plus the
nozzle line length for two heads (i.e., (n+4)×L). The length of the
short side of the periodic flushing box 131 is determined to be
substantially the height of the head plate 84, which has a parallelogram
shape in plan view, (i.e., the length in the X-axis direction). As shown
in FIG. 9, a plurality of ribs 133 (3 ribs) are arranged to protrude from
the bottom surface of the periodic flushing box 131 while extending in
the Y-axis direction. Sheet-shaped absorbent materials 134 for absorbing
the functional liquid are arranged on these ribs 133. The top surfaces of
the absorbent materials 134 substantially coincide with the top surface
plane of the periodic flushing box 131.

[0102]The box support rods 132 support the periodic flushing box 131 so
that the top surface plane of the periodic flushing box 131 is slightly
lower than the nozzle surface 97 of the functional liquid droplet
ejection heads 82 mounted on the head unit 13 (by 2 to 3 mm). The box
support rods 132 are secured to the slider body 51 of the X-axis air
slider 22 along with the set table 21. When the X-axis air slider 22
moves, the periodic flushing box 131 also moves in the X-axis direction
via a box stand. The box support rods 132 support the periodic flushing
box 131 at a position behind the set table 21. When the X-axis air slider
22 moves to allow the suction table 31 to be located at the workpiece
exchange position, the periodic flushing box 131 faces the head unit 13
to receive the functional liquid of the periodic flushing.

[0103]Although not shown, the periodic flushing box 131 includes a warpage
protection mechanism for preventing the warpage and deflection of the
absorbent materials 134. In this embodiment, a gap between the absorbent
materials 134 and the nozzle surface 97 of the functional liquid droplet
ejection heads 82 is small. Accordingly, if the absorbent materials 134
absorbs the functional liquid of the periodic flushing while curving
upward, the absorbent materials 134 expanded by the functional liquid may
be brought into contact with the nozzle surface 97. To solve this
problem, the warpage protection mechanism is provided to the periodic
flushing box 131. Thus, the occurrence of the warpage of the absorbent
materials 134 is prevented, and therefore, the absorbent materials 134 is
prevented from being brought into contact with the nozzle surface 97 of
the functional liquid droplet ejection heads 82.

[0104]The suction unit 15 sucks the functional liquid droplet ejection
heads 82 to force the ejection nozzles 98 of the functional liquid
droplet ejection heads 82 to discharge functional liquid. As shown in
FIG. 2, the suction unit 15 supports the head unit 13, namely, the seven
carriage units 81. The suction unit 15 includes seven divided suction
units 141 having the same structure arranged on the platform 5. Each of
the divided suction units 141 includes a cap unit 142 that approaches the
carriage units 81 to be sucked from their bottoms and causes twelve caps
143 to be brought into tight contact with the nozzle surfaces 97 of the
respective twelve functional liquid droplet ejection heads 82 mounted on
the carriage units 81, a cap elevation mechanism (not shown) for moving
the cap unit 142 up and down to allow the cap unit 142 to move towards
and away from the functional liquid droplet ejection heads 82 (the nozzle
surface 97), and sucking means (ejector: not shown) for sucking the
functional liquid droplet ejection heads 82 via the caps 143 in tight
contact with the functional liquid droplet ejection heads 82.

[0105]The functional liquid is sucked off in order to recover or prevent
clogging of the functional liquid droplet ejection heads 82 (the ejection
nozzles 98). Also, the functional liquid is sucked in order to fill the
functional liquid flow channels from the functional liquid tank to the
functional liquid droplet ejection heads 82 with the functional liquid
when a new liquid droplet ejection apparatus 1 is installed or the
functional liquid droplet ejection head 82 is replaced with a new one.
Additionally, the caps 143 are used to maintain the functional liquid
droplet ejection heads 82 when the liquid droplet ejection apparatus 1 is
not in use. In this case, the head unit 13 faces the suction unit 15 and
the caps 143 are brought into tight contact with the nozzle surfaces 97
of the functional liquid droplet ejection heads 82. Thus, the nozzle
surfaces 97 are sealed so as to prevent the functional liquid droplet
ejection heads 82 (the ejection nozzles 98) from drying.

[0106]The caps 143 of the suction unit 15 further function as flushing
boxes for receiving functional liquid ejected by the forcible ejection
(preliminary ejection) of the functional liquid droplet ejection heads
82. When only some of the carriage units 81 facing the suction unit 15
are sucked, the other carriage units 81 not to be sucked carry out the
forcible ejection to the caps 143. In this case, the caps 143 are moved
to the position where the top surfaces of the caps 143 are slightly
separated from the nozzle surfaces 97 by the cap elevation mechanism.

[0107]The wiping unit 16 wipes the nozzle surfaces 97 of the functional
liquid droplet ejection heads 82 using a wiping sheet 151 to which
cleaning liquid has been sprayed. As shown in FIG. 2, the wiping unit 16
includes a take-up unit 152 for feeding the wiping sheet 151 wound as a
roll and reeling the fed wiping sheet 151, a cleaning liquid supplying
unit 153 for spraying cleaning liquid to the fed wiping sheet 151, and a
wiping unit 154 for wiping the nozzle surfaces 97 with the wiping sheet
151 on which the cleaning liquid has been sprayed. The wiping operation
is carried out after the sucking operation of the suction unit 15 is
carried out, so that dust and dirt deposited on the nozzle surfaces 97
are wiped out. The wiping unit 16 is arranged at a position closer to the
X-axis table 11 than the suction unit 15. The wiping unit 16 faces the
head unit 13 (each carriage unit 81) returning to the home position after
the sucking operation by the suction unit 15 so that the wiping unit 16
can efficiently carry out the wiping operation.

[0108]Although not shown, each of the divided suction units 141 of the
suction unit 15 and the wiping unit 16 are supported by the unit
elevation mechanism so as to be lifted up and down. By moving down the
suction unit 15 (the divided suction units 141) and the wiping unit 16 to
a predetermined standby position, a working space can be ensured above
the suction unit 15 (the divided suction units 141) and the wiping unit
16 so that the suction unit 15 (the divided suction units 141) and the
wiping unit 16 can be maintained and the head plate 84 mounted on the
carriage unit 81 can be replaced.

[0109]As shown in FIG. 1 through 3 and FIG. 9, the ejection-defect test
unit 17 checks whether functional liquid is properly ejected from the
functional liquid droplet ejection heads 82 (the ejection nozzles 98)
mounted on the head unit 13. The ejection-defect test unit 17 includes
the drawn unit 161 for receiving functional liquid ejected for testing
from all of the ejection nozzles 98 of all functional liquid droplet
ejection heads 82 of the head unit 13 to draw a predetermined test
pattern; and an image capturing unit 162 for capturing an image of the
test pattern drawn on the drawn unit 161 to test it.

[0110]The drawn unit 161 includes a long drawing sheet 171 (e.g., roll
sheet) on which the test pattern is drawn, take-up means 172 for feeding
the drawing sheet 171 and reeling the fed the drawing sheet 171, a
take-up support member 173 for supporting the take-up means 172, and a
unit base 174 for supporting the take-up support member 173. The drawing
sheet 171 is loaded into the take-up means 172, which includes a feeding
reel 175 for unreeling the drawing sheet 171 and a take-up reel 176 for
reeling the drawing sheet 171, and a take-up motor (geared motor: not
shown) for rotating the take-up reel 176. The fed drawing sheet 171 moves
horizontally in the Y-axis direction while being exposed to the outside
and is reeled by the take-up reel 176. The horizontally moving portion of
the drawing sheet 171 serves as a drawn portion for receiving the test
pattern. The length of a long side of the horizontally moving portion in
the Y-axis direction is determined so that the horizontally moving
portion can receive test ejection from all of the functional liquid
droplet ejection heads 82 of the head unit. In this embodiment, like the
pre-drawing flushing boxes 121 and the periodic flushing box 131, the
length is determined to be the length of one drawing line plus the nozzle
line length for two heads.

[0111]The drawing sheet 171 is not reeled every time the test pattern is
drawn, but is reeled after the test pattern is drawn on the fed drawing
sheet 171a predetermined number of times. In this case, to prevent a test
pattern by each test ejection from overlapping with each other, a
currently drawn test pattern is slightly shifted from the previously
drawn test pattern in the X-axis direction. After the test pattern is
drawn a predetermined number of times so that the entire width of the
drawing sheet 171 is filled with the drawn test patterns, the take-up
motor is activated to reel the drawn drawing sheet 171 and feed the new
drawing sheet 171. In this embodiment, the drawing sheet 171 is
automatically reeled by the motor. However, in the case of infrequent
reeling operations, a manual take-up mechanism may be provided to reel
the drawing sheet 171 manually.

[0112]Additionally, in this embodiment, the drawing sheet 171 wound as a
roll is used to draw the test pattern. However, a glass substrate may be
used for the test pattern in place of the rolled drawing sheet 171. In
this case, the glass substrate is appropriately replaced with a new one.
However, the glass sheet on which the test pattern is drawn can be
repeatedly used after being cleaned.

[0113]The unit base 174 is disposed between the set table 21 and the
periodic flushing unit 112 and is supported by the slider body 51. The
take-up support member 173 supports the take-up means 172 between one of
the pre-drawing flushing boxes 121 adjacent to the periodic flushing box
131 and the periodic flushing box 131. Accordingly, when the suction
table 31 is moved to the workpiece exchange position to replace the
workpiece W after the drawing process, the drawing sheet 171 fed before
the periodic flushing box 131 faces the head unit 13 faces the head unit
13 so that a test pattern can be drawn on the drawing sheet 171.

[0114]As shown in FIG. 3, the image capturing unit 162 is supported by the
above-described Y-axis support bases 3 and faces the X-axis table 11 from
above. The image capturing unit 162 includes two test cameras 181 for
capturing an image of the test pattern drawn on the drawing sheet 171, a
camera holder 182 for holding the two test cameras 181, a camera moving
mechanism 183 which is secured to the Y-axis support bases 3 and which
supports the test cameras 181 via the camera holder 182 in a slidable
manner in the Y-axis direction, and a camera moving motor (not shown) for
moving the test cameras in the Y-axis direction via the camera moving
mechanism 183. The two test cameras 181 captures half images of the test
pattern drawn on the drawing sheet 171, respectively. For example, the
two test cameras 181 are arranged at a distance of substantially a half
length of one drawing line of the head unit 13 from each other. The two
test cameras 181 are moved so that the left test camera 181 captures the
left half of the test pattern and the right test camera 181 captures the
right half of the test pattern. Thus, the test pattern can be efficiently
image-captured (scanned) in a short time. As a result, the time required
for testing an ejection defect of the functional liquid droplet ejection
heads 82 can be reduced.

[0115]The image capturing unit 162 is arranged so that the two test
cameras 181 face the drawing sheet 171 when the suction table 31 is
located at the workpiece exchange position. In this embodiment, the image
of the test pattern can be captured during mounting and dismounting the
workpiece W. The image capturing result from the two test cameras 181 is
transmitted to the control means 18, by which the image is recognized. It
is then determined whether each of the ejection nozzles 98 of the
functional liquid droplet ejection heads 82 properly ejects functional
liquid, that is, it is determined whether each of the ejection nozzles 98
is clogged or not on the basis of the image recognition. This
determination is also made during mounting and dismounting of the
workpiece W. That is, the ejection-defect test unit 17 includes the image
capturing unit 162 and the control means 18.

[0116]Although not shown, a unit moving mechanism for slightly moving the
whole take-up means 172 in the X-axis direction is provided between the
unit base 174 and the take-up support member 173. As described above,
although the drawing position of the test pattern drawn on the drawing
sheet 171 is gradually shifted in the X-axis direction, the test pattern
can reliably face the fixed image capturing unit (the two test cameras
181) in the X-axis direction by moving the take-up means 172 in the
X-axis direction in accordance with the drawing position of the test
pattern.

[0117]In addition, an initial head alignment can be carried out by
adjusting the position of each of the carriage units 81 of the head unit
13 using the ejection-defect test unit 17 so that the divided drawing
lines form one straight drawing line.

[0118]A main control system of the liquid droplet ejection apparatus 1 is
described next with reference to FIG. 10. As shown in FIG. 10, the liquid
droplet ejection apparatus 1 includes a liquid droplet ejection unit 191
having the head unit 13 (the functional liquid droplet ejection heads
82); a workpiece moving unit 192 having the X-axis table 11 to move a
workpiece in the X-axis direction; a head moving unit 193 having the
Y-axis table 12 to move the workpiece in the Y-axis direction; a
maintenance unit 194 having all units of maintenance means; a detection
unit 195 having a variety of sensors to detect a variety of conditions; a
drive unit 196 having a variety of drivers to control the above-described
units; and a control unit 197 (the control means 18) connected to the
above-described units so as to perform overall control of the liquid
droplet ejection apparatus 1.

[0119]The control unit 197 includes an interface 201 for connecting each
means; a random access memory (RAM) 202 having a storage area capable of
temporarily storing data and used as a work area for control processing;
a read only memory (ROM) 203 having a variety of storage areas for
storing a control program and control data; a hard disk 204 for storing
drawing data used for drawing a predetermined drawing pattern on the
workpiece W, a variety of data from the units, and programs for
processing the variety of data; a central processing unit (CPU) 205 for
computing a variety of data under the control of programs stored in the
ROM 203 and the hard disk 204; and a bus 206 connecting these units to
each other.

[0120]The control unit 197 inputs a variety of data from the means via the
interface 201, allows the CPU 205 to compute the data under the control
of the programs stored in the hard disk 204 or programs sequentially read
out of a CD-ROM drive, and outputs the computation result to the means
via the drive unit 196 (a variety of drivers). Thus, the whole liquid
droplet ejection apparatus 1 is controlled and a variety of processing of
the liquid droplet ejection apparatus 1 is carried out.

[0121]A series of operations of the liquid droplet ejection apparatus 1
from the mounting operation of an unprocessed workpiece W on the set
table 21 (the suction table 31) to another mounting operation for the
next workpiece W is described below. When the workpiece W is mounted on
the suction table 31 at the workpiece exchange position by a robot arm (a
workpiece carrying-in-and-out apparatus: not shown), the control unit 197
drives the workpiece alignment cameras 62 to capture the image of the
workpiece W and image-recognizes the captured result. The control unit
197 then drives the θ table 32 on the basis of the recognition
result to correct the position (θ) of the workpiece W. During this
operation, the head unit 13 faces the periodic flushing unit 112 and the
periodic flushing operation of the functional liquid droplet ejection
heads 82 is carried out.

[0122]Upon completion of correcting the position of the workpiece W, the
control unit 197 completes the periodic flushing operation and drives the
X-axis table 11 to move the suction table 31 from the workpiece exchange
position to the position adjacent to the head unit 13. The control unit
197 then starts the above-described series of drawing operations. In this
embodiment, the area of the suction table 31 and the pair of pre-drawing
flushing boxes 121 attached to the suction table 31 is determined to be a
drawing area for the drawing process. During the series of drawing
operations, the X-axis table 11 is driven so that the head unit 13 faces
the inside of the drawing area and the suction table 31 (the workpiece W)
moves forward and backward. Accordingly, during the drawing process, the
pre-drawing flushing boxes 121 and the workpiece W sequentially face the
head unit 13 to carry out pre-drawing flushing and drawing on the
workpiece W. Since the periodic flushing unit 112 and the ejection-defect
test unit 17 that carry out no drawing process do not face the head unit
13, the drawing process can be efficiently and properly carried out.

[0123]After the functional liquid is ejected onto the workpiece W and the
drawing process (the second backward movement of the workpiece W in the
third drawing operation) is completed, the X-axis table 11 is
continuously driven so that the workpiece W is moved to the workpiece
exchange position. At that time, the control unit 197 drives the ejection
of all of the functional liquid droplet ejection heads 82 of the head
unit 13 to cause all of the functional liquid droplet ejection heads 82
to carry out test ejection. Thus, during the movement of the workpiece W,
the test pattern is drawn on the drawing sheet 171 of the ejection-defect
test unit 17 facing the head unit 13 (the functional liquid droplet
ejection heads 82). As described above, in this embodiment, by using the
moving operation of the workpiece W towards the workpiece exchange
position after the drawing process, the test pattern is drawn on the
drawing sheet 171. Consequently, since the head unit 13 need not move to
carry out the test ejection, the test pattern can be efficiently drawn.

[0124]When the workpiece W (the suction table 31) reaches the workpiece
exchange position, the control unit 197 stops driving of the X-axis table
11 and drives the Y-axis table 12 so that the head unit 13 returns to the
home position. The control unit 197 then causes the functional liquid
droplet ejection heads 82 of the head unit 13 to carry out an ejecting
operation of periodic flushing into the periodic flushing box 131 located
immediately beneath the head unit 13. Simultaneously, a robot arm (not
shown) retrieves the processed workpiece W and sets a new unprocessed
workpiece W on the set table 21.

[0125]Additionally, when the workpiece W reaches the workpiece exchange
position, the control unit 197 drives the camera moving motor to move the
two test cameras 181 in the X-axis direction. The two test cameras 181
capture the image of the test pattern drawn on the drawing sheet 171. The
control unit 197 then image-recognizes the captured image to determine
whether an ejection defect of each of the functional liquid droplet
ejection heads 82 of the head unit 13 occurs. If it is determined that
all of the functional liquid droplet ejection heads 82 properly eject
functional liquid, the ejection defect test is completed. After the
workpiece W is replaced, the control unit 197 stops the periodic flushing
operation and drives the X-axis table 11 so that the set table 21 is
moved towards the head unit 13 to carry out the next drawing process.

[0126]However, if it is determined that an ejection defect of the
functional liquid droplet ejection heads 82 occurs, a maintenance process
is carried out for the functional liquid droplet ejection heads 82. More
specifically, the carriage unit 81 including the faulty functional liquid
droplet ejection head 82 is moved to face the suction unit 15 (the
divided suction unit 141), which sucks the faulty functional liquid
droplet ejection head 82. The carriage unit 81 is then moved to face the
wiping unit 16, which carries out a wiping operation. In this embodiment,
the home position of the head unit 13 is located in the vicinity of the
suction unit 15 (and the wiping unit 16). Accordingly, when it is
determined that an ejection defect occurs, the head unit 13 at the home
position can rapidly moves and faces the suction unit 15 to carry out the
maintenance operation.

[0127]The head unit 13 according to this embodiment includes seven
independently movable carriage units 81. Consequently, when it is
determined that an ejection defect of the functional liquid droplet
ejection heads 82 occurs, all of the seven carriage units 81 need not
move to face the suction unit 15 or the wiping unit 16. For example,
when, as shown in FIG. 2, an ejection defect of the functional liquid
droplet ejection head 82 of the third carriage unit 81 from the left is
detected, the first to third carriage units 81 from the left are moved to
face the suction unit 15. The sucking operation is then carried out for
only the third carriage unit 81 from the left. In this case, the
functional liquid droplet ejection heads 82 of the carriage units 81 left
at the home position continue to carry out the periodic flushing
operation. For the normal carriage units 81 facing the suction unit 15,
the caps 143 of the suction unit 15 face the functional liquid droplet
ejection heads 82 with spaces therebetween. The functional liquid droplet
ejection heads 82 then carry out the flushing operation to the caps 143.

[0128]After the series of maintenance process of the carriage units 81
including the functional liquid droplet ejection heads 82 is completed
and the carriage units 81 which moved towards the suction unit 15 return
to the home position, the control unit 197 drives the X-axis table 11 so
that the drawing sheet 171 of the ejection-defect test unit 17 faces the
head unit 13 and another test pattern is drawn on the drawing sheet 171.
The operation similar to the above-described series of operations is
repeated. The head unit 13 moves to the home position to carry out the
periodic flushing operation. It is then determined whether the ejection
defect of the functional liquid droplet ejection heads 82 is recovered.

[0129]As described above, in the liquid droplet ejection apparatus 1
according to this embodiment, the image of the test pattern is captured
and the ejection defect is determined on the basis of the captured image
while the workpiece W is replaced. Accordingly, the time for mounting and
dismounting the workpiece W can be efficiently used, thus reducing the
total tact time. In addition, after the drawing process of the workpiece
W is completed, it is determined whether an ejection defect of each of
the functional liquid droplet ejection heads 82 of the head unit 13
occurs before the drawing process starts for a new unprocessed workpiece
W. Therefore, the manufacturing yield can be increased.

[0130]Additionally, in the liquid droplet ejection apparatus 1 according
to this embodiment, when the suction table 31 is moved to the workpiece
exchange position, the periodic flushing box 131 faces the head unit 13.
During the workpiece mounting and dismounting operation, the periodic
flushing is continuously carried out. Accordingly, during the workpiece
mounting and dismounting operation (and during the ejection defect
testing operation), the ejection nozzles 98 of the functional liquid
droplet ejection heads 82 can be effectively prevented from clogging. In
addition, the amount of functional liquid ejected from the functional
liquid droplet ejection heads 82 can be stably maintained. In particular,
since the periodic flushing box 131 is disposed on the moving axis of the
set table 21, the periodic flushing operation can continue until the
workpiece W starts to move from the workpiece exchange position (in order
to start a new drawing operation). Therefore, the functional liquid
droplet ejection heads 82 can be maintained in good conditions.

[0131]In this embodiment, like the pre-drawing flushing boxes 121, the
length of the periodic flushing box 131 and the horizontally moving
portion of the drawing sheet 171 of the drawn unit 161 is determined to
be the one drawing line length plus the nozzle line length for two heads
in order to cover the functional liquid ejection area of the head unit 13
for the drawing process. Accordingly, the periodic flushing operation may
be carried out during the moving operation of the head unit 13 from the
end position of the drawing process to the home position which is the
start position of the next drawing process. This results in a further
reduction of the stop time of the functional liquid droplet ejection
heads 82. As a result, the functional liquid droplet ejection heads 82
can be efficiently prevented from clogging.

[0132]When the head unit 13 carries out a drawing process while moving in
the sub scanning direction and when the drawing process of odd order
starts from the home position of the head unit 13 and the drawing process
of even order starts from the end position of the drawing process of the
odd order (i.e., the drawing process of odd order is carried out in the
direction opposite to that for the drawing process of even order), the
periodic flushing operation can be carried out whether the head unit 13
is positioned at the start position of drawing process of odd order or at
the start position of drawing process of even order.

[0133]The length of the periodic flushing box 131 and the horizontally
moving portion of the drawing sheet 171 of the drawn unit 161 may be
determined to be the one drawing line length. In this case, to receive
periodic flushing during the mounting and dismounting operation of the
workpiece W, the periodic flushing box 131 is arranged on the X-axis air
slider 22 to face the head unit 13 at the home position (adjacent to the
suction unit 15). The drawn unit 161 is arranged on the X-axis air slider
22 to face the head unit 13 so that the X-axis air slider 22 faces the
head unit 13 from the time the drawing process is completed until the
workpiece W moves to the workpiece exchange position.

[0134]Additionally, in this embodiment, the set table 21, the periodic
flushing unit 112, and the ejection-defect test unit 17 are mounted on
the same X-axis air slider 22 (the slider body 51). However, by dividing
the slider body 51 into two sliders independently slidable in the X-axis
direction by the X-axis linear motor, the set table 21 may be mounted on
one slider, and the periodic flushing unit 112 and the drawn unit 161 of
the ejection-defect test unit 17 may be mounted on the other slider. In
this case, when moving the set table 21 from the workpiece exchange
position and when moving the set table 21 to the workpiece exchange
position, the two sliders are integrally moved by the X-axis linear
motor. During the drawing process, the X-axis linear motor drives only
the slider on which the set table 21 is mounted to move forward and
backward for carrying out pre-drawing flushing and drawing on the
workpiece W.

[0135]In this embodiment, the workpiece W is moved in the main scanning
direction whereas the head unit 13 is moved in the sub scanning
direction. However, the head unit 13 may be moved in the main scanning
direction and the workpiece W may be moved in the sub scanning direction.
Alternatively, the workpiece W may be fixed and the head unit 13 may be
moved in the main scanning direction and the sub scanning direction. In
either case, as described above, by arranging the flushing unit 14 and
the ejection-defect test unit 17 on the main scan moving axis, the
flushing operation and the ejection defect test can be efficiently
carried out.

[0136]Furthermore, it should therefore be understood that the invention is
not limited to the particular embodiments described herein, but is
intended to include all changes and modifications that are within the
scope and spirit of the invention.

[0137]The structure and the manufacturing process of an electro-optic
device (flat panel display) manufactured using the liquid droplet
ejection apparatus 1 according to this embodiment are described below.
Examples of the electro-optic devices include a color filter, a liquid
crystal display device, an organic electroluminescent device, a plasma
display panel (PDP) device, an electron emission device (FED or SED
device), and an active matrix substrate composed of these devices. As
used herein, the term "active matrix substrate" refers to a substrate on
which a thin-film transistor and source and data lines electrically
connected to the thin-film transistor are formed.

[0138]A method for manufacturing a color filter incorporated in liquid
crystal display devices and organic electroluminescent devices is
described first. FIG. 11 is a flow chart illustrating the manufacturing
steps of the color filter. FIGS. 12A through 12E are schematic
cross-sectional views of a color filter 600 (filter base 600A) shown in
the manufacturing steps according to this embodiment.

[0139]In a black matrix forming step (S101), as shown in FIG. 12A, a black
matrix 602 is formed on a substrate (W) 601. The black matrix 602 is
formed from chromium metal, a laminate of chromium metal and chromium
oxide, or a resin black. The black matrix 602 can be formed from a thin
metal film by a sputtering method or a vapor deposition method.
Additionally, the black matrix 602 can be formed from a thin resin film
by a gravure printing method, a photo resist method, or a thermal
transfer method.

[0140]Subsequently, in a bank forming step (S102), a bank 603 is formed
while overlapping the black matrix 602. That is, as shown in FIG. 12B, a
resist layer 604 is formed using a transparent negative photosensitive
resin while covering the substrate 601 and the black matrix 602.
Thereafter, the top surface of the resist layer 604 is covered by a mask
film 605 formed in a matrix and then an exposure process is carried out.

[0141]As shown in FIG. 12C, the resist layer 604 is then patterned by
etching the unexposed portion of the resist layer 604. Thus, the bank 603
is formed. If the black matrix is formed with a resin black, the black
matrix can serve as the bank.

[0142]The bank 603 and the black matrix 602 beneath the bank 603 form a
partition wall 607b for separating pixel areas 607a from each other and
define projected areas of the functional liquid when the functional
liquid droplet ejection heads 82 form coloring layers (coating portions)
608R, 608G, and 608B in the subsequent coloring layer forming step.

[0144]In this embodiment, a resin material whose coating surface is
lyophobic (hydrophobic) is used for a material of the bank 603. Since the
surface of the substrate (glass substrate) 601 is lyophilic
(hydrophilic), the precision of the projected position of the droplet in
each of the pixel areas 607a surrounded by the bank 603 (the partition
wall 607b) is improved.

[0145]Subsequently, in the coloring layer forming step (S103), as shown in
FIG. 12D, the functional liquid droplet ejection heads 82 ejects a
functional liquid droplet into each of the pixel areas 607a surrounded by
the partition wall 607b. In this case, the functional liquid droplet
ejection heads 82 ejects functional liquid (filter material) of three R,
G, and, B colors. The arrangement pattern for R, G, and, B colors
includes a stripe arrangement, a mosaic arrangement, and a delta
arrangement.

[0146]Thereafter, a drying process (e.g., a heating process) is carried
out to fix the functional liquid. Thus, the three coloring layers 608R,
608G, and 608B are formed. After the three coloring layers 608R, 608G,
and 608B are formed, an overcoating step (S104) is carried out. As shown
in FIG. 12E, an overcoat 609 is formed to cover the top surfaces of the
substrate 601, the partition wall 607b, and the coloring layers 608R,
608G, and 608B.

[0147]That is, after liquid for the overcoat is ejected to the entire
surface on which the coloring layers 608R, 608G, and 608B of the
substrate 601 are formed, a drying process (e.g., a heating process) is
carried out to form the overcoat 609.

[0148]After the overcoat 609 is formed, a coating step is carried out, in
which Indium Tin Oxide (ITO) for forming a transparent electrode in the
subsequent step is coated.

[0149]FIG. 13 is a cross-sectional view of an essential part of the
structure of a passive matrix liquid crystal device (liquid crystal
device), which is one of the examples of a liquid crystal display device
using the color filter 600. By mounting a liquid crystal drive integrated
circuit (IC), a backlight, and a support member on a liquid crystal
device 620, a transmissive liquid crystal display device is achieved as a
final product. Since the color filter 600 is identical to that shown in
FIG. 12, the same components as those illustrated and described in
relation to FIG. 12 are designated by the same reference numerals, and
the descriptions thereof are not repeated here.

[0150]The liquid crystal device 620 includes the color filter 600, an
opposite substrate 621 composed of, for example, a glass substrate, and a
liquid crystal layer 622 composed of a super twisted nematic (STN) liquid
crystal composition and sandwiched by the color filter 600 and the
opposite substrate 621. The color filter 600 is disposed at the upper
side of FIG. 13 (adjacent to an observer).

[0151]Although not shown, a polarizer is disposed on each of the outer
surfaces of the opposite substrate 621 and the color filter 600 (the
surfaces remote from the liquid crystal layer 622). A backlight is
disposed outside the polarizer on the opposite substrate 621.

[0152]A plurality of evenly spaced long rectangular first electrodes 623
are formed on the surface of the overcoat 609 of the color filter 600
(adjacent to the liquid crystal layer 622) while extending in the
transverse direction of FIG. 13. A first alignment layer 624 is formed to
cover the surfaces of the first electrodes 623 remote from the color
filter 600.

[0153]In contrast, a plurality of evenly spaced long rectangular second
electrodes 626 are formed on the surface of the opposite substrate 621
facing the color filter 600 while extending in a direction perpendicular
to the first electrodes 623 of the color filter 600. A second alignment
layer 627 is formed to cover the surfaces of the second electrodes 626
adjacent to the liquid crystal layer 622. The first electrodes 623 and
the second electrodes 626 are formed from a transparent conductive
material, such as ITO.

[0154]Spacers 628 are disposed in the liquid crystal layer 622 to maintain
the thickness of the liquid crystal layer 622 (cell gap) to be constant.
A seal 629 prevents a liquid crystal composition in the liquid crystal
layer 622 from leaking to the outside. One end of each of the first
electrodes 623 functions as an interconnection line 623a and extends to
the outside of the seal 629. Areas where the first electrodes 623
intersect the second electrodes 626 serve as pixels. The liquid crystal
device 620 is designed so that the coloring layers 608R, 608G, and 608B
of the color filter 600 are positioned at these areas.

[0155]In a commonly used manufacturing process, the color filter 600 is
patterned to form the first electrodes 623. The first alignment layer 624
is then applied on the first electrodes 623 to achieve the color filter
600. The opposite substrate 621 is patterned to form the second
electrodes 626. The second alignment layer 627 is then applied on the
second electrodes 626 to achieve the opposite substrate 621. Thereafter,
the spacers 628 and the seal 629 are formed on the opposite substrate
621. The color filter 600 is then bonded to the opposite substrate 621.
Subsequently, after liquid crystal for forming the liquid crystal layer
622 is injected from an injection port of the seal 629, the injection
port is sealed. The two polarizers and a backlight are then layered.

[0156]According to this embodiment, for example, the liquid droplet
ejection apparatus 1 can apply a material of the spacers (functional
liquid), which forms the cell gap, while uniformly applying liquid
crystal (functional liquid) on an area surrounded by the seal 629 before
the color filter 600 is bonded to the opposite substrate 621. In
addition, the liquid droplet ejection apparatus 1 can print the seal 629
using the functional liquid droplet ejection heads 82. Furthermore, the
liquid droplet ejection apparatus 1 can apply the first alignment layer
624 and the second alignment layer 627 using the functional liquid
droplet ejection heads 82.

[0157]FIG. 14 is a schematic cross-sectional view of an essential part of
the structure of a liquid crystal device 630, which is a second example
of the liquid crystal device using the color filter 600 according to this
embodiment.

[0158]One of the main differences between the liquid crystal device 630
and the above-described liquid crystal device 620 is that the color
filter 600 is disposed at the lower side of the drawing (opposite to an
observer).

[0159]The liquid crystal device 630 includes the color filter 600, an
opposite substrate 631 formed from, for example, a glass substrate, a
liquid crystal layer 632 formed from STN liquid crystal and disposed
between the color filter 600 and the opposite substrate 631. Although not
shown, a polarizer is disposed on each of the outer surfaces of the
opposite substrate 631 and the color filter 600.

[0160]A plurality of evenly spaced long rectangular first electrodes 633
are formed on the surface of the overcoat 609 of the color filter 600
(adjacent to the liquid crystal layer 632) while extending in a direction
perpendicular to the plane of FIG. 14. A first alignment layer 634 is
formed to cover the surfaces of the first electrodes 633 adjacent to the
liquid crystal layer 632.

[0161]A plurality of evenly spaced long rectangular second electrodes 636
are formed on the surface of the opposite substrate 631 facing the color
filter 600 while extending in a direction perpendicular to the first
electrodes 633 of the color filter 600. A second alignment layer 637 is
formed to cover the surfaces of the second electrodes 636 adjacent to the
liquid crystal layer 632.

[0162]Spacers 638 are disposed in the liquid crystal layer 632 to maintain
the thickness of the liquid crystal layer 632 to be constant. A seal 639
in the liquid crystal layer 632 prevents a liquid crystal composition in
the liquid crystal layer 632 from leaking to the outside. Like the
above-described liquid crystal device 620, areas where the first
electrodes 633 intersect the second electrodes 636 serve as pixels. The
liquid crystal device 630 is designed so that the coloring layers 608R,
608G, and 608B of the color filter 600 are positioned at these areas.

[0163]FIG. 15 is a schematic exploded perspective view of a transmissive
thin-film transistor (TFT) liquid crystal device, which is a third
example of the liquid crystal display device using the color filter 600
according to the invention.

[0164]A liquid crystal display device 650 includes the color filter 600 at
the upper side of FIG. 15 (adjacent to an observer).

[0165]The liquid crystal device 650 includes the color filter 600, an
opposite substrate 651 opposed to the color filter 600, a liquid crystal
layer (not shown) sandwiched by the color filter 600 and the opposite
substrate 651, a polarizer 655 disposed on the upper surface of the color
filter 600 (adjacent to an observer), and a polarizer (not shown)
disposed on the lower surface of the opposite substrate 651.

[0166]A liquid crystal driving electrode 656 is formed on a surface of the
overcoat 609 of the color filter 600 (on the surface adjacent to the
opposite substrate 651). The electrode 656 is composed of a transparent
conductive material, such as ITO. The electrode 656 covers the entire
area in which pixel electrodes 660, which is described below, are formed.
An alignment layer 657 is formed to cover the surface of the electrode
656 remote from the pixel electrode 660.

[0167]An insulating layer 658 is formed on the surface of the opposite
substrate 651 remote from the color filter 600. Scanning lines 661 and
signal lines 662 are formed on the insulating layer 658 while being
perpendicular to each other. The pixel electrodes 660 are formed in areas
surrounded by the scanning lines 661 and the signal lines 662. Although
an alignment layer is formed on the pixel electrodes 660 in an actual
liquid crystal device, the alignment layer is not shown here.

[0168]A thin-film transistor 663 including a source electrode, a drain
electrode, a semiconductor, and a gate electrode is formed in an area
surrounded by a notch portion of each of the pixel electrodes 660, the
scanning line 661, and the signal line 662. By supplying signals to the
scanning line 661 and the signal line 662, the thin-film transistor 663
is turned on and off to control an electrical current supplied to the
pixel electrode 660.

[0169]In the above-described examples, the liquid crystal devices 620,
630, and 650 are of a transmissive type. However, by providing a
reflective layer or a semi-transmissive reflective layer to these liquid
crystal devices, transmissive liquid crystal devices or semi-transmissive
reflective liquid crystal devices can be produced.

[0170]FIG. 16 is a cross-sectional view of an essential part of the
display area of an organic EL display (hereinafter simply referred to as
a display device 700).

[0171]The display device 700 includes a substrate (W) 701, a circuit
element portion 702, a light-emitting element portion 703, and a negative
electrode 704, which are layered in this order.

[0172]In the display device 700, light emitted from the light-emitting
element portion 703 to the substrate 701 passes through the circuit
element portion 702 and the substrate 701 and is output to an observer.
At the same time, light emitted from the light-emitting element portion
703 to the side remote from the substrate 701 is reflected by the
negative electrode 704. The reflected light passes through the circuit
element portion 702 and the substrate 701 and is output to the observer.

[0173]A bedding overcoat 706 is formed between the circuit element portion
702 and the substrate 701. The bedding overcoat 706 is composed of a
silicon dioxide film. Semiconductor films 707 are formed on a surface of
the bedding overcoat 706 adjacent to the light-emitting element portion
703 in island forms. The semiconductor films 707 are composed of
polycrystalline silicon. A source region 707a and a drain region 707b are
formed on the left and right sides of the semiconductor films 707,
respectively, by high-concentration positive-ion implantation. The middle
region where positive ions are not implanted defines a channel region
707c.

[0174]A transparent gate insulating film 708 is formed in the circuit
element portion 702 while covering the bedding overcoat 706 and the
semiconductor films 707. Gate electrodes 709 are formed on the gate
insulating film 708 at positions corresponding to the channel regions
707c of the semiconductor films 707. The gate electrodes 709 are composed
of, for example, Al, Mo, Ta, Ti, and W. A first transparent insulating
interlayer 711a and a second insulating interlayer 711b are formed on the
gate electrodes 709 and the gate insulating film 708. Contact holes 712a
and 712b are formed while passing through the first and second
transparent insulating interlayers 711a and 711b and communicating with
the source region 707a and the drain region 707b, respectively.

[0175]Transparent pixel electrodes 713 are formed on the second insulating
interlayer 711b by patterning it with a predetermined shape. The
transparent pixel electrodes 713 are composed of, for example, ITO. The
pixel electrodes 713 are connected to the source regions 707a via the
contact holes 712a.

[0176]Power supply lines 714 are formed on the first transparent
insulating interlayer 711a. Each of the power supply lines 714 is
connected to the drain region 707b via the contact hole 712b.

[0177]Thus, in the circuit element portion 702, driving thin-film
transistors 715 are formed and are connected to the pixel electrodes 713.

[0178]The light-emitting element portion 703 includes a function layer 717
layered on each of a plurality of the pixel electrodes 713 and a bank 718
which is disposed between each of the pixel electrodes 713 and the
function layer 717 and which separates the function layer 717 from
another one.

[0179]A light-emitting element includes the pixel electrodes 713, the
function layer 717, and the negative electrode 704 disposed on the
function layer 717. The pixel electrode 713 is formed in a substantially
rectangular shape in plan view. The bank 718 is formed between the pixel
electrodes 713.

[0180]The bank 718 includes an inorganic bank layer (a first bank layer)
718a and an organic bank layer (a second bank layer) 718b layered on the
inorganic bank layer 718a and having a trapezoidal shape in cross
section. The inorganic bank layer 718a is composed of an inorganic
material, such as SiO, SiO2, or TiO2. The organic bank layer
718b is composed of a resist having high heat resistance and solvent
resistance, such as an acrylic resin or a polyimide resin. A part of the
bank 718 is formed to cover the periphery of the pixel electrode 713.

[0181]Between the banks 718, an opening 719 is formed. The size of the
opening 719 gradually increases upwards towards the pixel electrodes 713.

[0182]The function layer 717 is formed in the opening 719. The function
layer 717 includes a hole-injecting/hole-transporting layer 717a layered
on the pixel electrode 713 and a light-emitting layer 717b formed on the
hole-injecting/hole-transporting layer 717a. Another function layer may
be formed next to the light-emitting layer 717b. For example, an
electron-transporting layer may be formed next to the light-emitting
layer 717b.

[0183]The hole-injecting/hole-transporting layer 717a has a function to
transport a hole from the pixel electrode 713 to inject it into the
light-emitting layer 717b. The hole-injecting/hole-transporting layer
717a is formed by ejecting a first composition (functional liquid)
containing a material for forming a hole-injecting/hole-transporting
layer. A widely known material can be used as the material for forming a
hole-injecting/hole-transporting layer.

[0184]The light-emitting layer 717b emits light having one of the R, G,
and B color components. The light-emitting layer 717b is formed by
ejecting a second composition (functional liquid) containing a material
for forming a light-emitting layer (a light-emitting material). A widely
known material insoluble in the hole-injecting/hole-transporting layer
717a is preferably used as a solvent of the second composition (nonpolar
solvent). By using such a nonpolar solvent as the second composition for
the light-emitting layer 717b, the solvent does not dissolve the
hole-injecting/hole-transporting layer 717a again so as to form the
light-emitting layer 717b.

[0185]Thus, the light-emitting layer 717b allows a hole injected from the
hole-injecting/hole-transporting layer 717a and an electron injected from
the negative electrode 704 to unite and emit light.

[0186]The negative electrode 704 is formed to cover the entire surface of
the light-emitting element portion 703. The negative electrode 704 allows
an electrical current to flow in the function layer 717 in cooperation
with the pixel electrode 713. A seal material (not shown) is disposed on
the negative electrode 704.

[0187]The manufacturing process of the above-described display device 700
is described with reference to FIGS. 17 through 25.

[0188]As shown in FIG. 17, the manufacturing process of the display device
700 includes a bank forming step (S11), a surface processing step (S112),
a hole-injecting/hole-transporting layer forming step (S113), a
light-emitting layer forming step (S114), and an opposite electrode
forming step (S115). The manufacturing process is not limited to the
above-described steps. Some steps may be eliminated or some steps may be
added.

[0189]In the bank forming step (S111), as shown in FIG. 18, the inorganic
bank layer 718a is formed on the second insulating interlayer 711b. After
an inorganic film is formed on the second insulating interlayer 711b at a
desired position, the inorganic film is patterned by using a
photolithography technique to form the inorganic bank layer 718a. At that
time, the inorganic bank layer 718a partially overlaps the periphery of
the pixel electrode 713.

[0190]After the inorganic bank layer 718a is formed, the organic bank
layer 718b is formed on the inorganic bank layer 718a, as shown in FIG.
19. Like the inorganic bank layer 718a, the organic bank layer 718b is
formed by patterning using a photolithography technique.

[0191]Thus, the bank 718 is formed. At the same time, the opening 719
which is open above the pixel electrode 713 is formed between the banks
718. This opening 719 defines the pixel area.

[0192]In surface processing step (S112), a liquid affinity treatment and a
liquid repellency treatment are performed. The liquid affinity is
provided to areas of a first layer 718aa of the inorganic bank layer 718a
and an electrode surface 713a of the pixel electrode 713. The liquid
affinity is provided to these areas (surfaces) by, for example, a plasma
process using oxygen as processing gas. The plasma process also cleans
ITO of the pixel electrode 713.

[0193]The liquid repellency is provided to a wall surface 718s and a top
surface 718t of the organic bank layer 718b. The surfaces are treated
with fluorine to have liquid repellency by, for example, a plasma process
using tetrafluoromethane as processing gas.

[0194]This surface processing step results in reliable ejection of
functional liquid onto a pixel area when the function layer 717 is formed
by using the functional liquid droplet ejection heads 82. Additionally,
the functional liquid ejected onto the pixel area can be prevented from
leaking from the opening 719.

[0196]As shown in FIG. 20, in the hole-injecting/hole-transporting layer
forming step (S113), the functional liquid droplet ejection heads 82
eject the first composition containing the material for forming the
hole-injecting/hole-transporting layer into the openings 719, which are
the pixel areas. Thereafter, as shown in FIG. 21, polar solvent contained
in the first composition is vaporized by a drying process and a heating
process to form the hole-injecting/hole-transporting layer 717a on the
pixel electrode 713 (the electrode surface 713a).

[0197]The light-emitting layer forming step (S114) is described next. As
described above, in this light-emitting layer forming step, to prevent
re-dissolution of the hole-injecting/hole-transporting layer 717a, a
nonpolar solvent insoluble to the hole-injecting/hole-transporting layer
717a is used as the solvent of the second composition.

[0198]On the other hand, since the hole-injecting/hole-transporting layer
717a has low affinity with the nonpolar solvent, there is a possibility
that the hole-injecting/hole-transporting layer 717a is not brought into
tight contact with the light-emitting layer 717b or the light-emitting
layer 717b is not uniformly applied even though the second composition
containing the nonpolar solvent is ejected to the
hole-injecting/hole-transporting layer 717a.

[0199]Accordingly, to increase the affinity of the surface of the
hole-injecting/hole-transporting layer 717a with the nonpolar solvent and
the material forming the light-emitting layer, the surface treatment
process (surface reforming process) is preferably carried out before the
light-emitting layer is formed. In this surface treatment process, the
same solvent as the nonpolar solvent of the second composition, which is
used for forming the light-emitting layer, or a similar solvent is
applied to the surface of the hole-injecting/hole-transporting layer 717a
as a surface reforming material. The solvent is then dried out.

[0200]This process allows the surface of the
hole-injecting/hole-transporting layer 717a to have high affinity with
the nonpolar solvent, and therefore, the second composition containing a
material for forming the light-emitting layer can be uniformly applied to
the hole-injecting/hole-transporting layer 717a in the subsequent step.

[0201]As shown in FIG. 22, a predetermined amount of the second
composition containing a material for forming the light-emitting layer
corresponding to one of the three colors (blue (B) in the example in FIG.
22) is ejected to the pixel area (the opening 719) as functional liquid.
The second composition ejected into the pixel area spreads over the
hole-injecting/hole-transporting layer 717a. The opening 719 is filled
with the second composition. Even when the second composition is ejected
onto the top surface 718t of the bank 718 outside the pixel area, the
second composition easily moves into the opening 719 since the liquid
repellency is provided to the top surface 718t, as described above.

[0202]Thereafter, the drying step is carried out to dry the ejected second
composition. The nonpolar solvent contained in the second composition is
vaporized to form the light-emitting layer 717b on the
hole-injecting/hole-transporting layer 717a, as shown in FIG. 23. In FIG.
23, the light-emitting layer 717b corresponding to blue (B) color is
formed.

[0203]Similarly, as shown in FIG. 24, by using the functional liquid
droplet ejection heads 82, steps that are the same as those for the
above-described light-emitting layer 717b corresponding to blue (B) color
are sequentially carried out so as to form the light-emitting layers 717b
corresponding to the other colors (red (R) and green (G)). The order of
forming the light-emitting layer 717b is not limited to the
above-described order. The light-emitting layers 717b may be formed in
any order. For example, the order of forming can be determined depending
on a material for forming the light-emitting layer. In addition, the
array pattern for R, G, and B colors includes a stripe arrangement, a
mosaic arrangement, and a delta arrangement.

[0204]Thus, the function layer 717, namely, the
hole-injecting/hole-transporting layer 717a and the light-emitting layer
717b are formed on the pixel electrode 713. Thereafter, the opposite
electrode forming step (S115) is carried out.

[0205]In the opposite electrode forming step (S115), as shown in FIG. 25,
the negative electrode 704 (opposite electrode) is formed over the entire
surfaces of the light-emitting layer 717b and the organic bank layer 718b
by, for example, a vapor deposition method, a sputtering method, or a
chemical vapor deposition (CVD) method. In this embodiment, the negative
electrode 704 includes, for example, a laminate of a calcium layer and an
aluminum layer.

[0206]An Al film or an Ag film serving as an electrode is formed on the
negative electrode 704 as needed. An overcoat composed of, for example,
SiO2 or SiN is also formed on the Al film or the Ag film to protect
it from oxidization as needed.

[0207]After the negative electrode 704 is formed, a sealing process in
which the top surface of the negative electrode 704 is sealed with a
sealing member and other processes, such as a wiring process, are carried
out to achieve the display device 700.

[0208]FIG. 26 is an exploded perspective view of an essential part of a
plasma display device (PDP device: hereinafter simply referred to as a
display device 800). In this drawing, the display device 800 is partially
cut away.

[0209]The display device 800 includes a first substrate 801, a second
substrate 802 opposed to the first substrate 801, and a discharge display
portion 803 formed therebetween. The discharge display portion 803
includes a plurality of discharge chambers 805. Among the plurality of
the discharge chambers 805, a red discharge chamber 805R, a green
discharge chamber 805G, and a blue discharge chamber 805B form a set
serving as a pixel.

[0210]Address electrodes 806 are formed on the first substrate 801 in a
stripe pattern with a predetermined spacing therebetween. A dielectric
layer 807 is formed to cover the top surfaces of the address electrodes
806 and the first substrate 801. Partition walls 808 are vertically
arranged on the dielectric layer 807. Each of the partition walls 808 is
positioned between the address electrodes 806 while extending along the
address electrodes 806. Two types of the partition walls 808 are
provided: the partition walls 808 extending at both sides of the address
electrode 806 in its width direction, as shown in the drawing, and the
partition walls 808 extending perpendicular to the address electrodes 806
(not shown).

[0211]An area separated by the partition walls 808 serves as the discharge
chamber 805.

[0213]As shown in FIG. 26, a plurality of display electrodes 811 are
formed on the lower surface of the second substrate 802 in a stripe
pattern with a predetermined spacing therebetween while extending in a
direction perpendicular to the address electrodes 806. A dielectric layer
812 is formed to cover the display electrodes 811 and the second
substrate 802. A overcoat 813 is formed to cover the dielectric layer
812. The overcoat 813 is made of, for example, MgO.

[0214]The first substrate 801 is bonded to the second substrate 802 so
that the address electrodes 806 are perpendicular to the display
electrodes 811. The address electrodes 806 and the display electrodes 811
are connected to an alternate current power supply (not shown).

[0215]By applying an electrical current to each of the address electrodes
806 and the display electrodes 811, the fluorescent material 809 in the
discharge display portion 803 is excited to emit light, and therefore, a
color display can be obtained.

[0216]In this embodiment, the address electrodes 806, the display
electrodes 811, and the fluorescent material 809 can be produced by using
the liquid droplet ejection apparatus 1 shown in FIG. 1. The steps for
forming the address electrodes 806 on the first substrate 801 are
described below as an example.

[0217]In this case, the first substrate 801 is mounted on the set table 21
of the liquid droplet ejection apparatus 1. Thereafter, the following
steps are carried out:

[0218]The functional liquid droplet ejection heads 82 eject droplets of a
liquid material (functional liquid) containing a material for forming
conductive film lines onto areas where the address electrodes 806 are to
be formed. The liquid material contains conductive fine particles of, for
example, metal, which are dispersed in a dispersion medium and which
serve as the material for forming conductive film lines. Examples of
conductive fine particles include metal fine particles containing gold,
silver, copper, palladium, or nickel, and a conductive polymer.

[0219]After the liquid material is supplied to all of the areas where the
address electrodes 806 are to be formed, the ejected liquid material is
dried so that the dispersion medium contained in the liquid material
evaporates. Thus, the address electrodes 806 are formed.

[0220]In the foregoing description, the address electrodes 806 are formed.
However, the same forming steps can achieve the first substrate 801 and
the fluorescent material 809.

[0221]When forming the display electrodes 811, as in the step for forming
the address electrodes 806, the droplets of a liquid material (functional
liquid) containing a material for forming conductive film lines are
ejected onto areas where the display electrodes 811 are to be formed.

[0223]FIG. 27 is a cross-sectional view of an essential part of an
electron emission device (also referred to as an FED device or an SED
device: hereinafter simply referred to as a display device 900). In this
drawing, the display device 900 is partially shown in cross-section.

[0224]The display device 900 includes a first substrate 901, a second
substrate 902 opposed to the first substrate 901, and a field emission
display portion 903 formed therebetween. The field emission display
portion 903 includes a plurality of electron emission portions 905
arranged in a matrix.

[0225]A first element electrode 906a and a second element electrode 906b,
both of which form a cathode electrode 906, are formed on the first
substrate 901 such that the first element electrode 906a is perpendicular
to the second element electrode 906b. A conductive film 907 having a gap
908 therein is formed in an area partitioned by the first element
electrode 906a and the second element electrode 906b. That is, the first
element electrode 906a, the second element electrode 906b, and the
conductive film 907 form a plurality of the electron emission portions
905. The conductive film 907 is made of, for example, palladium oxide
(PdO). The gap 908 can be formed by a forming process after the
conductive film 907 is coated.

[0226]An anode electrode 909 is formed on the lower surface of the second
substrate 902 while facing the cathode electrode 906. Banks 911 are
formed on the lower surface of the anode electrode 909 in a lattice. A
fluorescent material 913 is disposed in each of openings 912 surrounded
by the banks 911 and extending downward while facing the electron
emission portion 905. The fluorescent material 913 emits fluorescent
light of one of red (R), green (G), and blue (B) colors. A red
fluorescent material 913R, a green fluorescent material 913G, and a blue
fluorescent material 913B are disposed in the openings 912 in the
above-described predetermined pattern.

[0227]The first substrate 901 having such a structure is bonded to the
second substrate 902 with a small gap therebetween. In the display device
900, an electron emitted from the first element electrode 906a or the
second element electrode 906b, which is a negative electrode, is hit on
the fluorescent material 913 formed on the anode electrode 909, which is
a positive electrode. The fluorescent material 913 is excited to emit
light, and therefore, a color display can be obtained.

[0228]Like the other embodiments, the first element electrode 906a, the
second element electrode 906b, the conductive film 907, and the anode
electrode 909 can be produced by using the liquid droplet ejection
apparatus 1. The fluorescent materials 913R, 913G, and 913B can also be
produced by using the liquid droplet ejection apparatus 1.

[0229]The first element electrode 906a, the second element electrode 906b,
and the conductive film 907 have shapes shown in FIG. 28A in plan view.
When these components are coated, a bank BB is formed in advance by using
a photolithography method while leaving areas where the first element
electrode 906a, the second element electrode 906b, and the conductive
film 907 are to be formed. Thereafter, the first element electrode 906a
and the second element electrode 906b are formed in grooves formed by the
bank BB by an inkjet process using the liquid droplet ejection apparatus
1. The solvents of the first element electrode 906a and the second
element electrode 906b are dried to coat them. The conductive film 907 is
then formed by an inkjet process using the liquid droplet ejection
apparatus 1. After the conductive film 907 is coated, the bank BB is
removed (by a resist stripping or ashing process). The above-described
forming process is then carried out. As in the step for forming the
above-described organic EL device, the liquid affinity is preferably
provided to the first substrate 901 and the second substrate 902, and the
liquid repellency is preferably provided to the banks 911 and the bank
BB.

[0230]Examples of other electro-optic devices include devices for forming
metal wiring, a lens, a resist, and a light diffuser. By using the
above-described liquid droplet ejection apparatus 1 for manufacturing a
variety of electro-optic devices, these electro-optic devices can be
efficiently manufactured.